PREVIOUSLY FILLED AUTOMATICALLY RETRACTABLE SAFE SYRINGE Russian patent published in 2017 - IPC A61M5/32 

FIELD: medicine.

SUBSTANCE: invention relates to medical equipment, namely to retractable syringes. Syringe comprises: cannula, hollow cylinder, folding piston and spring. Wherein cannula comprises first end for placement and retention of needle, passing in distal direction, located near first guide on external wall of cannula, and second end located opposite to first end. Hollow cylinder comprises inner surface limiting chamber, allowing to place cannula inside chamber of hollow cylinder with possibility of subsequent removal, distal open end allowing first end of cannula to project in distal direction, and it includes second guide appliance arranged nearby, on side wall of hollow cylinder, and proximal open end arranged opposite to distal open end. Folding piston is installed with possibility of sliding in hollow cylinder, it includes first piston element with proximal end and distal end, second piston element connected to first piston element with possibility of further removal. Wherein first piston element is made with ledge near distal end of first piston element, and second piston element comprises longitudinal slot on side wall of second piston element for placement of ledge of first piston element, enabling ledge to slide in lengthwise direction along longitudinal slot, and longitudinal slot includes proximal part with compressed zone for controlling ledge and distal part, so that first and second piston elements are connected until compressed zone is not deformed for release of ledge of compressed zone, enabling ledge to slide to distal part of longitudinal slot, thus first and second piston elements can slide axially relative to each other. Spring is located between cannula and internal surface of hollow cylinder, so that spring acts between cannula and hollow cylinder. Wherein cannula is further made with at least one channel for fluid medium passing in longitudinal direction through needle to place fluid medium in chamber; and first guide appliance is engaged with first part of second guide with possibility of subsequent removal, so that first and second guides are able to retain cannula with possibility of subsequent removal from spring expansion force until first guide comes out of engagement with first part of second guide and moves to second part of second guide to initiate retraction of cannula.

EFFECT: use of invention provides user-initiated automatic needle retraction, when force applied by user, exceeds specified mechanical strength, wherein syringe can be used once and it is less susceptible to fail retraction of improper use during injection.

15 cl, 5 dwg